Editing Willamette River (section)

==Flooding==
[[File:Willamette River 1996 flood aerial.jpg|thumb|alt=Flooding in 1996|An aerial view of the 1996 flooding]]
Due to the volume and seasonality of precipitation in western Oregon, the Willamette River has often flooded. Heavy rains and mountain snows are common in winter, and snowpack in the Cascade Range can rapidly melt during warmer winter storms.<ref name="Oregon Encyclopedia"/><ref name="1861flood">{{cite web |last=Allen |first=Cain |url=http://oregonhistoryproject.org/articles/historical-records/the-great-flood-of-1861/ |title=The Great Flood of 1861 |publisher=Oregon Historical Society |work=The Oregon History Project |year=2004 |access-date=June 17, 2016 |archive-url=https://web.archive.org/web/20160827132826/https://oregonhistoryproject.org/articles/historical-records/the-great-flood-of-1861/ |archive-date=August 27, 2016 |url-status=live}}</ref> The greatest Willamette River flood in recorded history began in 1861, well before the construction of dams in the watershed.<ref name="1861flood"/>

Rainstorms and warm temperatures in December 1861 combined with a well-above-average snowpack in the Cascades created the largest Willamette River flood in recorded history. An observer of the flood wrote, "The whole Willamette valley was a sheet of water".<ref name="1861flood"/> From Eugene to Portland, thousands of acres of farmland were washed away, and many towns in the valley were damaged or destroyed. The "[[Great Flood of 1862|Great Flood]]", as it is sometimes called, was massively destructive to human development because most of that development was located on the river's floodplain, which provided rich soils and ready access to water transportation. The 1861 flood peaked at {{convert|635000|cuft/s|m3/s}}—more than the [[Mississippi River]] usually discharges in the 21st&nbsp;century—and inundated some {{convert|353000|acre|km2}} of land.<ref name="Flooding" /><ref name="1861flood"/><ref>{{cite web |title=Mississippi River Anatomy: How Much Water Does the Mississippi Handle? |url=http://www.americaswetlandresources.com/background_facts/detailedstory/MississippiRiverAnatomy.html |publisher=America's Wetland Foundation |access-date=August 27, 2013 |date=June 1, 2012 |archive-url=https://web.archive.org/web/20160514051844/http://americaswetlandresources.com/background_facts/detailedstory/MississippiRiverAnatomy.html |archive-date=May 14, 2016 |url-status=live}}</ref> This flood destroyed the town of [[Linn City, Oregon|Linn City]]. When the flood ended on December 14, only three homes remained standing in Linn City. No one died in the Linn City flood, but the destruction was too significant for the town to recover, and it was abandoned. Today the city of [[West Linn, Oregon|West Linn]] stands about where Linn City once was.<ref name="BLM">{{cite web |last=Thomas |first=Mike |title=Linn City, Oregon: A Victim of Nature's Wrath |publisher=Bureau of Land Management |url=http://www.blm.gov/wo/st/en/res/Education_in_BLM/Learning_Landscapes/For_Kids/History_Mystery/hm3/linn_city.html |archive-url=https://web.archive.org/web/20160930010910/http://www.blm.gov/wo/st/en/res/Education_in_BLM/Learning_Landscapes/For_Kids/History_Mystery/hm3/linn_city. |archive-date=September 30, 2016 |url-status=dead}} 
</ref>

Significant flooding recurred in the winter of early 1890.<ref name="philadelphia record">{{cite news |title=The Floods and the Storm |url=https://news.google.com/newspapers?id=U8tVAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=4553%2C5634916 |access-date=July 2, 2011 |newspaper=The Philadelphia Record |page=1 |date=February 9, 1890}}</ref><ref name="great floods">{{cite news |title=Oregon's Great Floods |newspaper=The New York Times |date=February 7, 1890 |url=https://timesmachine.nytimes.com/timesmachine/1890/02/07/103228176.pdf |access-date=July 2, 2011}}</ref> Portland's main street was completely submerged, communication over the Cascades was cut off, and many rail lines were forced to shut down.<ref name="great floods" /> Another major flood occurred on the Willamette in 1894, and although it too caused much damage, it was not as large as that of 1861.<ref name="Flooding"/>

[[File:Aerial view of vanport flooded.jpg|thumb|left|alt=flooded Vanport in 1948|The remains of Vanport City in June 1948]]

Throughout the 1940s the Willamette continued to flood its valley. It washed out five bridges in Lane County in December 1942,<ref name="vancouver sun">{{cite news |title=Floods Wash Out Oregon Bridges |url=https://news.google.com/newspapers?id=F_ZlAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=6691%2C1835508 |access-date=July 2, 2011 |newspaper=The Vancouver Sun |date=December 1, 1942 |location=Vancouver, British Columbia |page=1}}</ref> caused seven deaths in Portland and evacuations in Eugene in January 1943,<ref name="RG 1-2-43">{{cite news |title=Lower River Areas Hit by Flood Crest |url=https://news.google.com/newspapers?id=W7BWAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=4605%2C2872262 |access-date=July 2, 2011 |newspaper=The Register-Guard |location=Eugene, Oregon |date=January 2, 1943 |agency=Associated Press |page=1}}</ref><ref name="flood peril">{{cite news |title=Flood Peril Wanes in Ohio Valley |url=https://news.google.com/newspapers?id=t1wiAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=3694%2C861829 |access-date=July 2, 2011 |newspaper=Reading Eagle |date=January 1, 1943 |agency=United Press International |location=Reading, Pennsylvania |pages=1, 18}}</ref> flooded Corvallis in November 1946,<ref name="SDC 1946">{{cite news |title=Willamette River Is Nearing Crest of Flood Stage |url=https://news.google.com/newspapers?id=RONXAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=7328%2C7090518 |access-date=July 2, 2011 |newspaper=The Spokesman-Review |date=November 28, 1946 |agency=Associated Press |location=Spokane, Washington |page=2}}</ref> contributed to the destruction of [[Vanport City, Oregon|Vanport City]] and the death of about 15 of its residents in May 1948,<ref>{{cite web |url=http://www.portlandoregon.gov/parks/finder/index.cfm?&propertyid=34&action=ViewPark |title=Delta Park |publisher=Portland Parks & Recreation |access-date=November 10, 2013}}</ref><ref>{{cite news |url=https://news.google.com/newspapers?id=miwfAAAAIBAJ&pg=4282,5836489&hl=en |title=After the Flood: Portland State Pays Tribute to Vanport Pioneers |newspaper=Daily Record |location=Ellensburg, Washington |date=October 4, 2001 |first=Landon |last=Hall |agency=Associated Press |page=B3 |access-date=August 26, 2013}}</ref> and nearly flooded parts of Salem in December 1948.<ref name="Salem flooding">{{cite news |title=River Flood Waters Reach Oregon Capital |url=https://news.google.com/newspapers?id=dsBkAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=1317%2C5881058 |access-date=July 2, 2011 |newspaper=Telegraph Herald |date=December 14, 1948 |agency=Associated Press |location=Dubuque, Iowa |page=16}}</ref>

Although the Willamette was, by the mid-20th century, heavily engineered and controlled by a complex system of dams, channels, and barriers, it experienced severe floods through the end of the century. Storms caused a [[Christmas flood of 1964|major flood]] that swelled the Willamette and other rivers in the Pacific Northwest from December 1964 through January 1965, submerging nearly {{convert|153000|acre|km2}} of land.<ref name="FEMA">{{cite web |last1=Gregory |first1=S. |last2=Ashkenas |first2=L. |last3=Jett |first3=S. |last4=Wildman |first4=R |url=http://www.fsl.orst.edu/pnwerc/wrb/Atlas_web_compressed/3.Water_Resources/3e.flood&fema_web.pdf |title=Flood Inundations/FEMA Floodplains: Floods and Floodplains in the Willamette River |publisher=Corvallis Forestry Research Community, Oregon State University |work=Willamette River Basin Atlas (2nd edition) |access-date=June 6, 2010 |archive-url=https://web.archive.org/web/20171209104055/http://www.fsl.orst.edu/pnwerc/wrb/Atlas_web_compressed/3.Water_Resources/3e.flood%26fema_web.pdf |archive-date=December 9, 2017 |url-status=dead}}</ref> Before dawn on December&nbsp;21, 1964, the Willamette reached {{convert|29.4|ft|m}}, which was higher than the seawall on its banks in Portland. By this time, about 15 people had died as a result of the flooding, and about 8,000 had been forced to evacuate their homes.<ref name="rampaging river">{{cite news |title=Portland Threatened by Rampaging River |newspaper=Tri-City Herald |date=December 21, 1964 |location=Kennewick, Washington |page=20}}</ref>

On December 24, 1964, President [[Lyndon B. Johnson]] ordered federal aid for the flooded areas as the Willamette continued to rise.<ref name="spoiled holiday">{{cite news |title=Floods Spoil Holiday in Oregon, California |url=https://news.google.com/newspapers?id=Nq4RAAAAIBAJ&dq=willamette%20flood%20-wiki&pg=7350%2C2520105 |access-date=June 29, 2011 |newspaper=The Spokesman-Review |date=December 25, 1964 |page=2 |location=Spokane, Washington}}</ref> In the next couple of days, the river receded, but on December&nbsp;27, it was at {{convert|29.8|ft|m}}, which was still nearly {{convert|12|ft|m}} above the flood stage.<ref name=reprieve>{{cite news |title=Portland Gets Reprieve from a Big Flood Threat |url=https://news.google.com/newspapers?id=-JUfAAAAIBAJ&dq=portland%20gets%20reprieve%20from%20a%20big%20flood%20threat&pg=1976%2C5832349 |access-date=June 29, 2011 |newspaper=The Nevada Daily Mail |date=December 27, 1964 |location=Nevada, Missouri |page=1}}</ref> The river continued to pose flood threats through January 1965,<ref name="pittsburgh press">{{cite news |agency=United Press International |date=January 30, 1965 |title=1000 Flee Flood in Northwest; Nation Shivers |newspaper=The Pittsburgh Press |url=https://news.google.com/newspapers?id=iF4bAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=6917%2C4443507 |page=1 |access-date=July 2, 2011}}</ref> and more stormy weather occurred along the Pacific Coast.<ref name="lewiston daily sun">{{cite news |agency=Associated Press |date=February 6, 1965 |title=Eastern Deep Freeze Eases, but Rain Brings Flood Fears to West |newspaper=The Lewiston Daily Sun |location=Lewiston, Maine |page=1 |url=https://news.google.com/newspapers?id=GsZGAAAAIBAJ&dq=willamette%20river%20flood%20-wiki&pg=6981%2C2178938 |access-date=July 2, 2011}}</ref>

{{quote box|align=right|width=33%|quote = The river crested at one town after another—at Corvallis 3½ feet above flood stage, Oregon City 18 feet above, Portland 10.5 feet above—much like a meal moving through a boa constrictor.|source= —Associated Press, February 10, 1996<ref name="Deseret News">{{cite news |agency=Associated Press |date=February 10, 1996 |title=Swollen River Spares Downtown Portland |newspaper=The Deseret News |location=Salt Lake City |page=A4 |url=https://news.google.com/newspapers?id=X_BHAAAAIBAJ&dq=the%20river%20crested%20at%20one%20town%20after%20another%20like%20a%20meal%20moving%20through%20a%20boa%20constrictor&pg=6510%2C5004315 |access-date=June 25, 2011}}</ref>}}

In February 1996, heavy warm rains driven by a subtropical [[jet stream]] fell on a deep snowpack in the Willamette watershed. These conditions, similar to those that caused the 1861 flood, caused [[Willamette Valley Flood of 1996|some of the costliest flooding in the river's recorded history]].<ref>{{cite web |last=Taylor |first=George H. |url=http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/6134/SR%20no.%20970_ocr.pdf?sequence=1 |title=The Great Flood of 1996: Its Causes and a Comparison to Other Climate Events |publisher=Oregon State University |date=November 1996 |page=2 |access-date=August 3, 2011}}</ref> An [[Associated Press]] journalist reported, "The river crested at one town after another—at Corvallis 3½ feet above flood stage, Oregon City 18 feet above, Portland 10.5 feet above—much like a meal moving through a boa constrictor."<ref name="Deseret News"/> The flood was serious enough to interrupt the progress of Oregon's growing economy,<ref>{{cite news |last=Barnard |first=Jeff |agency=Associated Press |title=Flood Spreads in Economy Like Muddy Water |url=http://nl.newsbank.com/nl-search/we/Archives?p_product=RM&p_theme=rm&p_action=search&p_maxdocs=200&p_topdoc=1&p_text_direct-0=0EB4E49FC4CAF785&p_field_direct-0=document_id&p_perpage=10&p_sort=YMD_date:D&s_trackval=GooglePM |access-date=June 26, 2011 |newspaper=Rocky Mountain News |date=February 25, 1996 |location=Denver}}</ref> but the inundated acreage was smaller than in 1964—only about {{convert|117000|acre|km2}}.<ref name="FEMA"/>

About 450 concrete flood-protection walls in Portland that had been constructed during the February flood, each weighing about {{convert|5500|lb|kg}}, were removed in April 1996.<ref>{{cite news |title=Flood Wall Comes Down Today in Portland |url=https://news.google.com/newspapers?id=ZEdWAAAAIBAJ&dq=willamette%20river%20flood%201996%20-wiki&pg=5507%2C82622 |access-date=June 26, 2011 |newspaper=The Register-Guard |date=April 1, 1996 |location=Eugene, Oregon |page=3C}}</ref> In October, they were replaced by a larger steel wall that cost the city about $300,000. The new wall had {{convert|0.25|in|mm|adj=on}} removable steel plates designed to better prevent future flooding.<ref>{{cite news |agency=Associated Press |date=October 14, 1996 |title=Flood Wall Readied for Next Time |newspaper=The Register-Guard |location=Eugene, Oregon |page=5C |url=https://news.google.com/newspapers?id=MUxWAAAAIBAJ&dq=willamette%20steel%20plates%20-wiki&pg=1859%2C3852913 |access-date=June 27, 2011}}</ref>